Sheet metal rocker arm, manufacturing method thereof, cam follower with said rocker arm, and assembling method thereof

Abstract

A sheet metal rocker arm manufactured by the steps of punching one metal plate to form a blank having a predetermined contour and through holes, and subjecting this blank to a bending work based on a press work to form a pair of side walls parallel to each other and a connecting portion for connecting the both ends of the side walls in the width direction thereof. This rocker arm is also provided with at least a pair of though holes formed at positions which are aligned with each other on the both side walls and at least one engagement portion provided in a part of the connecting portion. The thickness of at least one engagement portion, is formed to be greater than the thickness of the both side walls.

What is claimed is:  
     
       1. A method of manufacturing a sheet metal rocker arm having a pair of side walls parallel to each other, a connecting portion for connecting end of both side walls in a width direction of the rocker arm, at least a pair of through holes formed at positions which are aligned with each other on both side walls for inserting a pivot cam follower, and an engagement portion provided in a part of said connecting portion, 
       said manufacturing method comprising:  
       first punching, second bending and third forming press work,  
       wherein a width of the connecting portion is reduced compared to that at the first punching step.  
     
     
       2. A method of manufacturing a sheet metal rocker arm having a pair of side walls parallel to each other, a connecting portion for connecting ends of both of the side walls in a width direction of the rocker arm, at least a pair of first through holes formed at positions which are aligned with each other on side walls for inserting a pivot of a cam follower, and an engagement portion provided in a part of said connecting portion, 
       said manufacturing method comprising:  
       punching a sheet of metal plate to form a blank having a predetermined contour and a second through hole having four corners;  
       bending said blank to form both of the side walls, and concurrently forming the connecting portion; and  
       forming part of the connecting portion to an engagement portion;  
       wherein said second through hole after the punching step has a recess at each of the corners.